Improved orthopedic procedures have made joint replacement and augmentation techniques commonplace. In total hip arthroplasty, both the femoral or ball aspect of the joint as well as the acetabular or socket portion are replaced with prosthetic implants. A wealth of references exist in this field, and many patents have been issued with respect to the implants themselves, as well as the tools used in such procedures and various methods associated with such procedures.
Although different techniques have been proposed to ensure correct placement of the femoral portion of a hip replacement, techniques associated with the implantation of acetabular prostheses are far less developed. There are several reasons for the lack of progress in this area. First, perhaps, exposure and resection of the femoral shaft is surgically more straightforward, facilitating a wider variety of alignment procedures. Access to the acetabulum is more challenging since the pelvic region, unlike the femoral counterpart, is relatively stationary during surgery, and the bones comprising the socket region to accept the implant are geometrically more complex, particularly if considerable deterioration or deformity are present.
This situation has led to the use of imperfect techniques associated with prosthetic acetabula implantation, often involving the use of manually operated instrumentation which relies only on the surgeon's hand and eye coordination to install the implant, occasionally relying upon visual markers. Existing tools in this area are described in U.S. Pat. Nos. 5,037,424, 5,116,339, 5,141,512, and 5,527,317.
With the increasing awareness that alignment accuracy fosters implant longevity, the need remains for instrumentation and/or techniques associated with the positioning an implant relative to a bone so as to achieve a desired orientation. Such advances could assist in the alignment of the acetabular component during hip arthroplasty, for example, to ensure a co-acting joint which more faithfully reproduces natural movements and reduces complications such as dislocation and wear.